The invention is in the field of inserting a nasal tube through the nose into the trachea or esophagus of a patient.
As is known, endotracheal and naso-gastric tubes are inserted into a patient through the nose for purposes which include the administration of anesthesia, ventilation of airways, and pumping of stomach fluids.
When intubation is through the nose, the attending physician can encounter a number of potential problems. Customarily, the intubation consists of simply inserting a flexible plastic hollow tube through a nostril, feeding it through the nasal cavity, the nasopharynx and oropharynx into the trachea or esophagus.
As is known, nasal intubation can traumatize the nasal mucosa, causing bleeding. Such trauma can result from laceration of - or formation of a submucosal "false channel" through - the mucosa. Often it is difficult to distinguish the resistance of mucosa from the resistance presented by the turbinates and a tube can be channeled through the mucosa with the application of sufficient pressure.
Insertion of an endotracheal tube through the nasal passageway is greatly facilitated by application or a local anesthetic to the mucosa in order to relieve discomfort. Frequently, in order to decrease mucosal swelling and to suppress bleeding resulting from abrasion of the mucosa, a vasoconstrictor is also applied topically. Presently, there is no effective way to topically apply an anesthetic or a vasoconstrictor in the nasal passageway prior to or concurrently with intubation.
Nasal insertion of an endotracheal tube frequently results in the transport of bacteria-laden mucus from the nose and nasopharynx to the trachea. This can result in pneumonia or systemic infection, as is borne out by the frequent incidence of measurable blood-borne bacteria after nasal intubation.
Finally, difficulty is often encountered in "making the corner" between the nasal cavity an the oropharynx; as shown in FIG. 1, the near 90.degree. transition between the nasal cavity 10 and the oropharynx 12 is difficult to traverse and the tip 14 of an endotracheal tube 16 can lacerate or perforate the posterior wall of the oropharynx in attempting to round the corner.
A number of prior art devices are available for facilitating the introduction of tubes into the trachea or esophagus. Such devices are primarily for guiding tubes through the oropharynx into the proper passageway. In this regard, a naso-gastric tube insertion guide is disclosed in U.S. Pat. No. 4,175,564, which teaches the use of an arcuate, perforated tube formed from rubber or plastic which is fed through the mouth into the pharynx and then the esophagus. A naso-gastric tube is then fed through the positioned guide to the stomach. If used in the nose, this guide would pose the same danger to the nasal mucosa and posterior pharynx as the naso-gastric tube itself: the sharp edges of the distal end of the guide can abrade or channel through the nasal mucosa and lacerate the rear of the oropharynx during insertion. Further, such a guide makes no provision for topicalization with local anesthetics prior to or during insertion. Another curved guide tube for feeding an endotracheal tube through the mouth into the trachea is taught in U.S. Pat. No. 4,211,234. Again, this guide can traumatize throat tissue and has no provision for topicalization.
The prior art also provides other means for feeding tubes through curved bodily passageways by the provision of guide tubes having contours which conform to the contour of the passageways (U.S. Pat. No. 3,754,554) or by flexible members which are manipulated by an operator to assume the contour of a passageway into which at tube is being fed (U.S. Pat. Nos. 3,802,440 and 4,244,362).
None of the prior art intubation guide devices address the problems discussed above. Their use in the nose would still present the potential of tissue injury and the devices make no provision for topicalization.